A Soil Recipe.

There is no soil on Mars or Venus.

How come? Those planets have plenty of rocks. Mars has windstorms that erode rocks into dust. Venus has an acid atmosphere that cooks rocks into new chemicals.
But there's still something missing. Without life, there is no soil. Living things haven't just made a home in the soil on our planet. Life actually made the soil as we know it.

Here's the recipe: First, select a large quantity of bedrock. You can start with a fresh lava flow, a solid granite dome, or some limestone. When weathered, or broken down, it will become the parent material that will make the next batch of soil.

Physical weathering: Next, break some of the parent material into pieces. Use a glacier to grind off big boulders and fine sediment. Wind or running water work great to make small mineral particles. Be patient. This can take several thousand years.

Chemical weathering: Now change some of the parent material and the mineral particles into other kinds of minerals. Run water over limestone to dissolve the limestone and make the water more acidic. Expose fresh rock with iron in it to the air to oxidize the rock. This can also take a while. But you can go on to the next step while this cooks.

Biological actions: Finally, start with some early colonizers like lichens. Then throw in a stock made of microscopic decomposers. These include bacteria, fungi, and protozoa. They all make humus out of dead organic matter. They also turn minerals from the parent material into nutrients that plants can use. Pretty soon you'll have enough humus for plants to begin growing. Your soil will now start to have a distinct structure. Instead of being just dust or sand, it will clump together. Water will stay longer instead of draining away.Soils are as diverse as the plants and animals growing and living above them. Tropical rain forest soil is not like a prairie soil. Physical, chemical, and biological actions work together to create every soil on the planet. But there are many ingredients that can go into the basic recipe